Q. Is there a big difference between hardware and software reverbs?

By Hugh Robjohns

Dedicated effects processing hardware, such as the TC Powercore Compact, offers a way to make use of the latest reverb plug-ins without placing additional demands on the host computer's CPU.

How much difference is there between the quality of a VST reverb plug-in and a hardware reverb processor such as the Lexicon PCM81 or the TC Electronic M One XL?

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Technical Editor Hugh Robjohns replies: Digital reverb effects, or at least reverb effects that try to emulate real spaces with some degree of accuracy, involve a great deal of complex digital data processing. While it is perfectly possible to run the algorithms in a PC or Mac environment using the host processor, the maths involved places huge demands on the CPU. As a result, even on the most up-to-date and powerful systems there will be a practical limit to the number and complexity of reverb processors that can be run while doing everything else you may want the computer to do.
Hardware reverbs are dedicated to doing just one thing, and so can be heavily optimised in terms of the processing power and electronic design.

Up until recently, most native reverb plug-ins used relatively simple algorithms and were often audibly inferior to even quite modest hardware reverbs. The advent of software convolution has improved matters considerably, and many of these new convolution reverb plug-ins sound as good as hardware units in many situations (to my ears at least).

Another very good alternative is to use embedded hardware processing like the TC Powercore or Universal Audio UAD1 cards. These offer dedicated DSP power to avoid clogging up the host processor, and allow advanced algorithms (often transcoded from hardware processors) to be run. The advantage is that everything is still under computer control, and so settings can be instantly saved with specific projects, which makes remixing or revising a project later on much quicker and easier than trying to find your settings notes (if you remembered to write them down!) and/or reconfiguring a hardware unit.


Published October 2005